In diagnostic and operative retinal practice, binocular indirect ophthalmoscopy is widely accepted as a fundamental method of examination of the retina of an eye. Typically, an indirect ophthalmoscope includes illuminating optics for illuminating the retina and viewing optics through which the image of the retina is viewed, and is mounted on a headband which enables it to be attached to the head of a user. The ophthalmoscope is used in conjunction with a hand held condensing ophthalmoscopy lens which the user positions between the viewing optics and the eye under examination so as to form an image of the retina between the lens and the viewing optics.
Compared with direct ophthalmoscopes, indirect ophthalmoscopes provide a relatively wide field of view and bright illumination of the retina under examination. However, this view is of a relatively low magnification.
It has been proposed to improve the magnification of an indirect ophthalmoscope by re-configuring the viewing optics so that the latter act as telescopes. However, this increases the complexity of the viewing optics and can adversely affect the size and weight of the ophthalmoscope. In addition, such an ophthalmoscope is no longer suitable for providing low magnification views.